Six years after seeing his business partner shot dead in the South Auckland shop they ran together, a liquor store owner has had a painful reminder of the past.

Gurwinder Singh, owner of Riverton Liquor where Navtej Singh was murdered, was recently injured in another robbery at the same store.

Singh is now calling for harsher penalties on those who target vulnerable behind-the-counter workers.

On June 9, 2008 a group of hooded men - one brandishing a .22 rifle - burst into Riverton Liquor in Manurewa.

Navtej Singh and Gurwinder Singh, who had owned the place for only three months, tried to calm the men.

CCTV showed Gurwinder Singh with his hands in the air begging the gunman not to shoot but moments later he aimed at Navtej Singh's stomach from only metres away and fired.

Within 16 seconds of entering the shop, the masked men made off with $4000 from the till and a couple of boxes of beers.

Gurwinder Singh could only watch as Navtej, a father of three, lay bleeding to death.

The Sikh businessman, speaking this week to the Sunday Star-Times from another of his liquor stores in Howick, confirmed a similar incident had recently taken place at the site of the murder.

On April 16, two men entered the store and grabbed an 18 pack of ready-to-drink bourbon and cola before attempting to make their escape.

Otara residents Eti Eti, 18, and Celestine Tinomana, 20, were arrested on May 31 and appeared in Manukau District Court on Friday accused of stealing the booze. They also face a charge of aggravated wounding.

It is unknown whether the alleged offenders had weapons.

Singh said he was injured in the aftermath, as he pursued the men, but did not want to go into detail about the extent of the violence.

He was similarly reluctant to discuss how the incident had reminded him of the harrowing ordeal of six years ago.

One thing that has not changed since 2008 was Singh's lack of faith in the justice system.

He labels the courts as "too soft" after only Anitelea Chan Kee of the six on trial for the murder of Navtej Singh was found guilty of murder.

And he is sceptical about how severely the latest alleged offenders will be treated.

After the death of dairy owner Arun Kumar in West Auckland a couple of weeks ago, Singh called for a legal overhaul to protect those behind the counter.

"If they're not changing the law, nothing happens. It's a waste of time. New Zealand needs to make a stricter law," he said.

"What has happened after six years? What did they change? Nothing. It's still the same things happening now."